Thermal injury is the most important mechanism of lesion formation during radiofrequency catheter ablation procedures. Irreversible tissue injury requires heating to approximately 50 °C. Temperatures above 100 °C result in coagulum formation. As temperature plays a major role during radiofrequency catheter ablation procedures, temperature monitoring has been recommended as a tool to help catheter ablation procedures. The results of recent clinical studies show that electrode temperatures do not vary at successful and failed ablation sites; electrode temperature does not predict or remove the possibility of arrhythmia recurrence .
Development of innovative fibers for mid-IR spectral range paves way for a number of promising fiber applications ranging from 2 to 18 µm. Many years of art photonics’ research and development for reliable IR-fiber technologies resulted in the final selection of the main IR-materials suitable for production of mid IR-fibers of optical performance acceptable for pragmatic applications.
Unique PIR-fibers are produced from the crystals of silver halide solid solution AgCl: AgBr. PIR-fiber transmission consists of the so called “finger-print” region of the spectrum (3 to 16 µm) – the most information rich for specific absorption bands of several molecular vibrations. In contrast to the most IR materials AgCl: AgBr crystals are non-hygroscopic, non-toxic and can be extruded by plastic deformation under elevated temperature and high pressure.
An improved production technology of PIR-fibers and assembly of durable PIR-cables, result in their high mechanical and optical parameters for reliable utilization in an extensive temperature range from 5 K to > 410 K with no deterioration of all those parameters.
Industrial types of PIR-cables are also made so robust that they withstand certain vibration and climatic tests.
Infrared Thermography System
An important example for application of PIR-fibers coupled with IR-detectors is the flexible 2D & 3D IR-imaging systems. Such IR-fiber systems facilitate remote temperature sensing at a long distance from IR-source – up to 20 m.
The Securus Medical Group, Inc. developed the novel Infrared Thermography System (IRTS) based on single PIR fiber. This remote temperature monitoring fiber system offers rapid, contact-independent, thermal mapping over the complete circumference of a 60 mm length of esophagus.
An infrared thermography catheter was inserted through the oropharynx into the esophagus, and guarantees real-time monitoring of the high-resolution thermal image on internal Esophagus wall in order to prevent overheating of the heart tissue during the radiofrequency ablation of atrial fibrillation.
IRTS was successful for continuously monitoring thermal parameters in the esophagus during RFA. This system exposed that esophageal temperature patterns during the pulmonary vein isolation are intricate in time and space and enabled measurement of dynamic patterns that would be impossible with conventional sensors.
“Esophageal infrared thermography during atrial fibrillation ablation”. Image credit: Art Photonics GmbH
 Crozier I, Daly M, Lim G, Roper G. Heart Rhythm. 2015 Nov; 12(11):2362-3. doi: 10.1016/j.hrthm.2015.07.037. Epub 2015 Aug 3
This information has been sourced, reviewed and adapted from materials provided by art photonics GmbH.
For more information on this source, please visit art photonics GmbH.